This invention relates to invalid hoists for use with slings in which invalids are suspended during lifting.
It is known from GB-A-2184706 to provide an invalid hoist with a lifting arm, a sling hanger support which is supported for angular displacement relative to a lifting arm of the hoist about a vertical axis, a sling hanger which is pivotable about a horizontal axis relative to the sling hanger support and which presents spaced sling attachment points on both sides of the horizontal axis, and means for retaining the hanger in alternative angular positions about said horizontal axis. The preferred retaining means, and indeed that used in practice, has been frictional means allowing the hanger to be infinitely adjustable in position throughout an operative range of angular movement. The drawback of this arrangement is that the frictional restraint to movement about said horizontal axis imposes a strain on an attendant, particularly on the wrists of the attendant, and especially when an operating handle of the hanger is in a raised position.
It is known from GB-A-2327931 to replace the frictional restraint with rotary drive means for pivoting the sling hanger about the aforesaid horizontal axis and switch means for selectively rotating the rotary drive means in one or other of two opposite directions. The rotary drive means are provided adjacent to the pivot axis between the sling hanger and the sling hanger support. This suffers from the disadvantage that the rotary drive means are not sealed from ingress of water when the hoist is used in bathing environments.
The present invention seeks to overcome this latter drawback.
According to the invention there is provided an invalid hoist comprising a lifting arm, a sling hanger support angularly displaceable relative to the lifting arm about a vertical or substantially vertical axis and a sling hanger which is of unitary construction pivotable about a horizontal axis relative to the sling hanger support and which presents two spaced sling attachment points on one side of the horizontal axis and at least one sling attachment point on the other side of the horizontal axis for connection of a first pair of sling attachments to one side of the horizontal axis and for connection of a second pair of sling attachments to the other side of the horizontal axis, rotary drive means for pivoting the sling hanger about said horizontal axis relative to the sling hanger support and switch means for selectively rotating the rotary drive means in one or other of two opposite directions, wherein the sling hanger support is of inverted generally U-shaped configuration having a cross member and two parallel or substantially parallel limbs depending from the cross member, the sling hanger is pivotably connected to the lower ends of the depending limbs and the rotary drive means comprises a power unit supported by the sling hanger support at or adjacent to the cross member and a transmission system connecting the power unit to the sling hanger for pivoting the sling hanger relative to the sling hanger support.
Preferred and/or optional features of the invention are set forth in claims 2 to 12, inclusive.
The invention will now be more particularly described, by way of example, with reference to the accompanying drawings.